1.Field of the Invention
The present invention relates generally to a system for determining the angular displacement of an object from a reference surface and, more particularly, to an improved system which is microprocessor controlled and utilizes a simple mechanical transducer in combination with fiber optic circuitry to determine such angular displacement.
2.Description of the Prior Art
Presently, systems for determining the angular displacement of an object from a reference surface are commercially available. One known system employs a transducer which is fixed to the object. The transducer is formed from a Linear Variable Differential Transformer (LVDT) and a spring and weight assembly. The gravitational force of the weight is exerted on the movable core of the LVDT and this gravitational force is opposed by a compression force exerted by the spring. When an angle of inclination exists between the object and the reference surface, the gravitational force of the weight changes. The gravitational force is determined by the formula, gravitational force (F)=m.times.g.times.cos X, where m is the mass of the weight, g is the gravitational constant, and X is the angle of inclination measured from the vertical. Under this condition, the weight force F acting against the spring is reduced. As the weight force F is reduced the core of the LVDT moves, changing the magnetic coupling between the LVDT primary and secondary coils and causing the output voltage of the LVDT to change. This change in LVDT output voltage is detected and the magnitude of the change is converted into an electrical signal representative of the angular displacement between the object and the reference surface.
Although this well-known system which utilizes an LVDT/spring and weight assembly transducer is capable of determining the angular displacement between an object and a reference surface, it is not without problems. For example, since this transducer is formed from a relatively large number of mechanical parts, part wear and friction generated as mechanical parts move can cause an inaccurate angular measurement to be made. In addition, since this transducer also includes electrical components, electrical failures can also cause inaccurate angular measurements.
Consequently, a need exists for an improved system for determining the angular displacement between an object and a reference surface which utilizes a transducer of simple mechanical design to eliminate both the mechanical and electrical difficulties experienced by presently utilized systems which employ combined LVDT/spring and weight assembly transducers.